Multi-story sifting device and method



May 16, 1961 P. BRUNINGHAUS MULTI-STORY SIFTING DEVICE AND METHOD Filed Dec. 22, 1958 1 J r mm M m WW,

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Ill n United States Paten'tO MULTI-STORY SlFTlNG DEVICE AND METHOD Paul Bruninghaus, Remscheid-Lennep, Germany, assignor to Rheinische Werkzeugund Metallwarenfabrik G.m.b.H., Remscheid-Luttringhausen, Germany, a corporation of Germany Filed Dec. 22, 1958, Ser. No. 792,688

7 Claims. (Cl. 209-319) This invention is in the field of sifting or screening machines and is concerned with a new and improved screening arrangement and method which has advantage in multi-story or multi-deck machines and single deck units as Well.

A primary object of the invention is a sifting or screening machine with interchangeable frame units so that a multi-story machine may be built up from standard parts.

Another object is a screening or sifting machine with accurate support and simple adjustment of inclination of the screening medium to increase the durability of the mesh and the output of the machine in consonance with the particular fraction desired.

Another object is a sifting machine in which highfrequency sinusoidal operations with superposed harmonies are imposed on a screening mesh or medium.

Another object is a method of sitting with a multistory unit.

Other objects will appear from time to time in the ensuing specification and drawings in which:

Figure l is a perspective of a multi-deck unit; and

Figure 2 is a side view of a variant form.

'In the drawings, Figures 1 and 2 show slightly different forms, but the same reference numerals will be used except where they differ. A main frame, indicated generally at 10, may support a plurality of screening units, indicated generally at 12. The frame may include a plurality of frame sections 14 which may be interchangeable and are shown as mounted one on top of the other by interfitting corner joints 15. Each such frame section may include corner posts or uprights 16 and lateral braces or rods 18. The lower end of the corner posts 16 may have pins which may be inserted in the top of the corner posts of the section below. The lowermost or base frame section 20 may have extended legs which support the entire structure.

Each screen unit 12 may include a generally rectangular sub-frame or deck 22 which supports a screening medium or mesh disposed at an inclined angle so that material fed to the high end will move down across the medium toward the low end. The mesh may be supported or clamped between rubber or felt pads or any suitable rubberlike material so that vibrations imparted to the mesh will not be abruptly terminated at the marginal edges. The frame may support a plurality of oscillators or electromagnets or heads 24, each of which has a rod connected directly to or otherwise associated with the screening medium or mesh at its lower end so that high-frequency sinusoidal oscillations may be im parted to the mesh at well spaced localized points to create radiating concentric vibrations which overlap and interfere in the intermediate areas. A screening device and method of this type is shown in US. Patent No. 2,880,871, issued April 7, 1959, of which this is a continuation-in-part.

Each screening unit may have an inlet 26 at or adjacent its upper end. A collecting or lower cone 28 may 2 be attached to and disposed below the sub-frame so that material or undersize that passes through the mesh or medium will be collected and channeled to a suitable conduit 30. The conduit may be adjustably connected to the lower end of the collecting cone to feed to the inlet for the next screening unit. The topmost frame section, as at 32, may have a suitable infeed hopper 34 for supplying material to the first screening unit. Each unit may have suitable spouts or discharges 36 which may be provided with tiltable lids 38, pivoted about its upper edge for removing or discharging oversize material.

Each frame section is shown with tracks 39 which extend along or between the laterial braces or rods 18 and are suitably supported by uprights 40. These tracks may accept rollers 42 which are mounted on suitable axles connected to the sides of each of the screen units adjacent the high end. A suitable turnbuckle or the like, designated 44, may be attached to the top of one of the oscillators 24 or at any suitable point adjacent the low end of each of the sub-frames so that an adjustment thereof will vary the angle of inclination of the deck. it should be noted that raising or lowering of the low end may be followed by movement of the sub-frame on its rollers along the tracks.

The frames may be assembled from single units, each unit being complete, so that the desired number may be used, one superimposed on top of another. Units may be either added or withdrawn, as required. It should be noted that the frame sections 14 are interchangeable and may be the same size.

In Figure 2, the connection 30 between the bottom of the collecting cone or funnel and the inlet 26 for the next screening or sifting unit may be flexible. Figure 1 varies somewhat therefrom in that this connection is made with a suitable feeding device 48 which may inelude an adjustable outlet and a vibrator element, not shown, suitably attached to the back of the spout or conduit. For example, the vibrator might be an electro mechanical head, similar to the ones indicated at 24. Such a unit would set up vibrations in the feeding device so that the material would be uniformly and evenly discharged therefrom into the inlet for the screening unit or from one screening unit to the next.

The frame may have a suitable electrical panel 52 for the various controls, electrical connections, etc., but the location and disposition of this panel is not important.

At times it is advantageous to further process the oversize material from one or more of the tiers of the machines. For example, in Figure 2, if the over-size from the center deck or unit is desired to be further processed, a suitable spout or receiving funnel, indicated generally at 50, may be suitably disposed below the discharge 38, for the over-size. The material may be conveyed by the funnel or spout to a separate screening unit, similar to those shown in the drawings.

The use, operation and function of the invention are as follows:

The frame sections may be interchangeable and as many decks as desired may be superimposed one on top of the other, depending on the number of fractions or separations to be taken. The material to be separated is poured in the upper hopper 34 and is discharged onto a suitable conveyor or the like from the collecting cone on the lower unit, as at 46.

Any number of screening units may be used. The mesh from one unit to the next may all be the same. In this case the screening intensity or eifectivenes of each unit may be varied by regulating the angle of inclination. For example, in a three story unit, the upper screen may be at a small angle, the second screen at a larger angle and the third screen at still a larger angle and the mesh fabric may be identical. This has the advantage when that the units may be interchangeable and the screening effectiveness may be properly adjusted by merely regu-' lating the angle of inclination.

This method of grading or separating is important. The finer the mesh, the more delicate it normally is. In cases of micro-sifting, the mesh normally wears out very quickly. It accordingly may be of advantage to use coarser mesh fabrics coupled with a greater angle of inclination, but still obtain a product of the same quality, since the greater the angle of inclination, the'finer the separation. While the greater tilt angle increases the durability of the mesh, it also increases the output due to the greater speed of travel of the material over the screen.

In a three story unit, for example, the mesh may be identical with the angle of inclination increasing from one unit to the next. This has the advantage that each sub-frame or deck may be interchangeable with any of the others. So, only one or two stand-by screens or spare frames need be available fitted with the mesh fabric. In the event of damage or excessive Wear to one mesh, the stand-by unit may be quickly inserted and down time will be substantially reduced.

It should be noted that each screen deck is supported on a three point suspension, the two rollers and the adjusting device 44. The roller is supported on each side adjacent its upper end and the adjusting device may be connected toward the lower and generally in the center. The three point support is a rigid foundation for the vibrations that may result from the electromagnets. Each unit may be supplied with a suitable dosaging device, as at 48, so that the material will be sprayed evenly and uniformly over the whole width of each of the screens. Any suitable indicators may be attached to the screens to precisely and easily indicate the actual angle of inclination.

With these and other objects in mind, it is therefore wished that the invention he unrestricted, except as by the appended claims.

I claim:

1. In a multiple screening device, a generally upright common frame, a plurality of screening units on the common frame arranged in series, adjusting means for each unit for independent vertical and horizontal adjustment thereof, discharge means for each unit for passing the material on to the next unit, the common frame including a plurality of superposed interchangeable frame sections, one on top of the other, each supporting at least one screening unit.

2. In a multiple screening device, a generally upright common frame, a plurality of screening units on the common frame arranged in series, oneabove weather in general vertical alignment, adjusting means for each unit for vertical adjustment including a pivot, the common frame including a plurality of superposed interchangeable frame sections, one on top of the other, each supporting at least one screening unit, and discharge means for. each unit for passing the material on to the next unit.

3. The structure of claim 2 further characterized in that the adjusting means is constructed to adjust each unit independently both vertically and horizontally.

4. The structure of claim 2 further characterized in that the adjusting means includes rollers for supporting each unit toward one end, tracks on the frame sections for the rollers providing bodily movement of the units, and means for raising and lowering the other end of each unit.

5. The structure of claim 2 further characterized by and including a base frame with legs supporting the interchangeable frame sections.

6. A method of operating a screen device with screening mesh of a given mesh size, including the steps of positioning a plurality of independent similar sections of such screening mesh in series, one above the other, all sections being of the same mesh size and interchangeable, inclining each section to the horizontal so that material to be sifted will move by gravity from the high to the low end, increasing the angle of inclination of the sections from top to bottom so that the sifting effectiveness of the sections to the material will increase going down, vibrating the thus disposed sections, and passing material to be sifted over the sections in order from top to bottom to separate the material into various sizes.

7. The method of claim 6 further characterized by and including the steps of positioning the sections directly above each other, and alternating the direction of inclination from one section to the next below it.

References Cited in the file of this patent UNITED STATES PATENTS 810,682 Stafer et al. Jan. 23, 1906 1,864,940 Reynold June 28, 1932 1,941,212 Johnson Dec. 26, 1933 2,226,503 Ramsey Dec. 24, 1940 2,374,775 Parks May 1, 1945 2,714,953 Wolski Aug. 9, 1955 2,880,871 Bruninghaus Apr. 7, 1959 

